Lock



FIG. 1 is a pesrepctive view of a lock showing my new design;

FIG. 2 is a top plan view thereof;

FIG. 3 is a front elevational view thereof;

FIG. 4 is a bottom plan view thereof;

FIG. 5 is a rear elevational view thereof;

FIG. 6 is a left side elevational view thereof; and,

FIG. 7 is a right side elevational view thereof.

The broken lines immediately adjacent to the shaded areas represent the boundaries of the claimed design. Other broken lines lines represent the portions of the design form no part of the claimed design. None of the broken lines form part of the claimed design. 

I claim the ornamental design for a lock, as shown and described. 